Since at least PostgreSQL 8.3, PostgreSQL indexes NULL using a bitmap on the index. That means "yes" it's indexed. Except it takes a bit, rather than a byte[s]. There is no speed advantage insofar as btree indexes are concerned with using a non-valueNULL value. It will work just as you'd expect.

Since at least PostgreSQL 8.3, PostgreSQL indexes NULL using a bitmap on the index. That means "yes" it's indexed. Except it takes a bit, rather than a byte[s]. There is no speed advantage insofar as btree indexes are concerned with using a non-value.

Since at least PostgreSQL 8.3, PostgreSQL indexes NULL using a bitmap on the index. That means "yes" it's indexed. Except it takes a bit, rather than a byte[s]. There is no speed advantage insofar as btree indexes are concerned with using a non-NULL value. It will work just as you'd expect.

Since at least PostgreSQL 8.3, PostgreSQL indexes NULL using a bitmap on the index. That means "yes" it's indexed. Except it takes a bit, rather than a byte[s]. There is no speed advantage insofar as btree indexes are concerned with using a non-value.